<!DOCTYPE html>
<link rel="author" title="Tim Nguyen" href="https://github.com/nt1m">
<link rel="help" href="https://drafts.csswg.org/css-sizing-4/#valdef-width-fit-content">
<link rel="match" href="fit-content-block-size-fixedpos-ref.html">
<style>
#container {
  height: fit-content;
  position: fixed;
  top: 50%;
  background-color: gold;
  margin: auto;
  bottom: 0;
}
</style>
<div id="container">
  <div style="height:90vh;width:50px;outline: 2px dotted red;"></div>
</div>
